An organic electroluminescence element (organic EL element) has been used as a self-luminous element to serve as an image display device, such as a display, and to serve as a surface light source. Here, such an organic EL element is generally prepared by sequentially laminating a transparent electrode serving as an anode, an organic layer, and a metal electrode serving as a cathode on a transparent supporting substrate, such as a glass substrate and a transparent plastic film. Therefore, by a voltage applied between the transparent electrode and the metal electrode, an electron supplied from the cathode and a hole supplied from the anode are recombined at the organic layer. Then, when an exciton thus generated transits from an excited state to a ground state, EL emission occurs. Light of the EL emission goes through the transparent electrode, and then is extracted to the outside from the transparent supporting substrate side.
However, in such an organic EL element, there has been a problem that light generated in the organic layer cannot be sufficiently extracted to the outside. To be more specific, most part of the light generated in the organic layer either disappears as heat while repeating multiple reflection within the element or is wave-guided within the element and exits from an end part of the element. Accordingly, there has been a problem that a sufficient efficiency in the extraction to the outside cannot be achieved. Therefore, for example, Japanese Unexamined Patent Application Publication 2002-260845 (Document 1) discloses a technique for solving such a problem. However, even by adopting such a technique, a sufficient efficiency in the extraction to the outside cannot be achieved.